Does high ranked sites can really help you rank faster??

I'm a little bit confused about that.. I'm always using high ranked sites but my site doesn't improved so well..

Can anyone answer that question??

I assume you mean that you are backlinking from highly ranked and high PA domains.
Could be several reasons
1) Your content sucks/is duplicate/adds no value.
2) Your not waiting long enough to see any returns.
3) The links your getting aren't really as great as you believe.
4) You haven't done enough backlinking.

You're talking about back linking maybe you should wait a little longer, both of them are useful. High PA and related sites are good with good contains.

be sure to insert the links within the content, with anchor variation
or if your just creating accounts to insert your links on the User Info and get 1backlink you should improove your strategy